Cages have been used for many years to hold check valves in registration with fluid passageways for controlling the flow of fluid, commonly pressurized fluid, therethrough.
Fluid-operated devices, particularly slack-adjusting devices, have employed such cages for many years for enabling a check valve to control pressurized, incompressible, fluid flow into a semi-chamber which changes in volume due to the movement of a spring-biased piston for a vehicular engine slack adjuster or chain or belt tensioner well known to those skilled in the art.
The cages in such devices have most commonly been held in place by featuring circular outwardly extending flanges that are adapted to rest in a recess surrounding the passageway for the fluid and are held thereagainst by means of a coiled spring.
Examples of prior art check valve cages employing such means to hold the cages in place in slack adjusting devices are disclosed in U.S. Pat. Nos. 4,098,240; 4,184,464; and 4,227,495, and examples employing such means for holding the cages in place in chain or belt tensioning devices are disclosed in U.S. Pat. Nos. 4,507,103; 4,713,044; and 4,708,696, the disclosures of all of which are incorporated herein by reference.
Although such cages may be utilized in the combination of the present invention, the cage is preferably of the type described in U.S. patent application Ser. No. 343,232, filed Apr. 26, 1989, now U.S. Pat. No. 4,894,047 and assigned to Eaton Corporation, in that it is held in place in an entirely different manner enabling elimination of the coiled spring and inwardly facing groove and/or retaining clip heretofore used for such purpose.
The present invention provides a combination of a cage, such as heretofore described, and a plunger having a retainer adapted to hold a second check valve in registration with the first check valve for enabling entrapped air to escape into a third chamber that includes an exit orifice for enabling entrapped air to escape therefrom.